Piano plates



p 7, 1965 R. c. BQEHME 3,204,509

PIANO PLATES Original Filed April 4, 1960 JNVENTOR. ROBERT C. BOEHME WWW ATTORNEYS United States Patent Original application Apr. 4, 1960, Ser. No. 19,820. Di-

vrded and this application Sept. 12, 1963, Ser. No.

2 Claims. (Cl. 84-188) This application is a division of copending application Serial No. 19,820, filed April 4, 1960, in the name of Carl Ultes, Jr., and Robert C. Boehme.

This invention relates to piano plates, particularly to improved piano plate constructions incorporating integrally formed individual bearing surfaces for the strings cooperating to make up a single note.

As more fully explained in the copending application of Carl Ultes, Jr., Serial No. 19,820, filed April 4, 1960, and assigned to the same assignee as this application, a piano plate, upon and over which the piano strings are strung in tension, requires various desirable properties which are, in a sense, inconsistent. One requirement is that of high vibration damping capacities, so that the plate will not vibrate in resonance with the strings. While various materials have been, at one time or another, employed for this purpose, the art for many years has found that castings of gray cast iron may be formed which have high damping capacity While in addition providing the necessary strength for supporting the high loads exerted thereon due to tensioning of the many strings of the piano. This tensioning may be non-uniform, being adjusted by the tuner, since the proper tuning of a string or strings which sounds a particular note is determined by tension and mass, in cooperation with a fixed length (variable between strings) which is known as the speaking length of the string. Obviously, once the piano is properly tuned there may be higher tensions in various strings with respect to other strings.

The strings are supported directly by the plate, which may receive tuning pins in a predetermined section thereof. In the case of upright pianos, the tuning pins generally are placed at the top of the plate for accessibility to the tuner, who must manipulate the tuning pins while at the same time striking the keys. For essentially the same reason the tuning pins in grand piano plates, mounted generally horizontal, are usually all located toward the section of the plate located to the front of the piano. The ends of the strings are suitably fastened to the tuning pins, and may pass around or through agraifes or guide pins in the plate which serve to locate the strings with respect to each other. The strings also may pass over bearing surfaces or beads at the top and bottom (or front and back in the case of grand plates) and beyond the bottom bearing the strings pass around or are secured to hitch pins which provide a fixed anchorage therefor.

As is well known, the majority of the notes of a piano are formed of two or three extents of a string from top to bottom, while a minority of the notes, essentially in the lower bass section, are formed of heavier strings which extend only from top to bottom, without return. Thus, in three-string note sections a given string may be fastened at one of its ends to a tuning pin, hooked around a hitch pin at the lower section of the plate, and passed upwardly to another tuning pin to which its opposite end is secured. Therefore, the one piece of string wire actually forms two strings of the piano, and these strings may or may not be in the same note.

Accordingly, the primary object of this invention is to provide a novel piano plate construction which includes specially formed individual bearing surface elements which, by reason of their integral formation with the Patented Sept. 7, 1965 plate itself, provide a speaking length essentially the same for several strings making up one note.

Another object of this invention is to provide such a novel piano plate construction which is by reason of its integral design inherently less expensive to manufacture.

Another object of the invention is to provide a novel piano plate construction incorporating integrally formed string bearing surfaces which extend substantially perpendicuar to the direction in which strings are placed over such surfaces, and in which separate such bearing surfaces are provided for engaging only those strings forming a single note, thereby assuring that the speaking length of different strings forming the same note is essentially the same.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings 1 FIG. 1 is an elevational view of a piano plate in accordance with the invention, including portions of some of the strings to show the general placement thereof;

FIG. 2 is a detail view on an enlarged scale of the upper left corner of FIG. 1; and

FIG. 3 is an enlarged partial perspective detail, showing a portion of FIG. 2, and emphasizing the novel agraife and bearing surface constructions provided by this invention.

Referring to the drawing, which illustrates some pre ferred embodiments of the invention, FIG. 1 is an overall view of a so-called overstrung plate for an upright type of piano. It should be understood, however, that this particular type of plate is described merely for purposes of explanation, and that the features of this invention may be applied to other plates, for example plates for grand pianos which may or may not be overstrung, and which are normally mounted in a horizontal plane. The plate is formed as an integral casting of gray cast iron and includes an upper string mounting section 10 and lower string mounting sections 12 and 14. These sections are joined by cross bars 15, 16, 17 and 18 which provide the necessary top and bottom strength and rigidity, while leaving relatively large apertures through the plate, thereby reducing the weight thereof.

The main set of strings, some of which are shown at 20, extends from the upper mounting section 10 to the lower mounting section 12, while the longer strings, a few of which are indicated at 22, particularly the bass section extend from the upper section 10 to the lower section 14, passing over the main strings 20 intermediate their lengths. Hence, this type of string mounting and this type of plate is generally known as an overstrung construction. In the upper mounting section 10 there are formed a plurality of apertures 25 which receive tuning pins 27 (FIGS. 2 and 3) mounted in suitable bushings (not shown) and about which ends of the wire strings are engaged and wrapped.

The strings extend from one tuning pin downwardly and around hitch pin members indicated generally at 30, on the lower section 12, and thence back again to another tuning pin. In passing from the tuning pins the strings engage over a bearing surface or bead 32 which may be conveniently formed as an integral inverted V- shaped bead projecting from the plate, and likewise in the lower sections 12 and 14 the strings pass over and in en- E5 in known manner at the lower end of the strings and hooked over the appropriate hitch pin.

In such construction, and referring particularly to FIG. I

engages with the strings and the sounding board, may

vary somewhat between strings of the same note, due to the angular direction of the upper mounting surface with respect to the path in which the springs are placed. In accordance with the invention the multi-string notes may .be provided with individual bearing surfaces, in the form of individual ridge-like projections 40 which extend essentially perpendicular to the strings, and which are of such length that they engage only those strings common to a particular note.

Furthermore, by reason of the relatively small size of these protuberances or projections forming the hitch pin members, and also the agraffes and bearing surfaces, they .will become chilled and hardened when the plate is cast,

whereas the heavier areas (i.e. the major portion) of the plate cool more slowly and provide the desired high vibrational damping capacity. The hardened surfaces of the hitch pin members 30, agraffes 38, and the various bearing surfaces, provide desirable wear resistant characteristics and particularly are capable of resisting the high 10- cal pressures exterted thereon by the strings when tensioned, substantially preventing embedding of the strings in such surfaces.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. A piano plate of the character described, comprising a cast metal body including upper and lower string mounting sections between which the strings are extended, means providing hitch pin anchorages in said lower section about which the strings may be Wrapped in passing from one tuning pin to another, string bearing surfaces formed as a plurality of separate integral projections from the surface of at least one of said sections in predetermined alignment with certain of the corresponding hitch pin anchorages over which the strings are placed, said bearing surfaces extending substantially perpendicular to the direction in which strings are placed thereon, and each bearing surface being of suflicient length to engage only those strings cooperating to form a single note.

2. A piano plate of the character described comprising a unitary casting of metal which provides a high vibration damping capacity and which has suflicient strength to resist relatively great forces exerted by mounting of strings under substantial tension from the top to the bottom across one face thereof, said casting including upper and lower string mounting sections between which the piano strings are extended, reinforcing cross members extending between said mounting sections for strengthening thereof and defining therewith substantially large openings through said casting which reduce the total weight thereof while maintaining the desired strength, sockets formed in said upper section for receiving tuning pins to which the ends of strings are attached and around which the strings are pulled for tensioning and tuning, a plurality of integral relatively narrow projections having hardened string engaging surfaces capable of resisting high pressure exerted thereon by tensioning of the strings in contact therewith, said projections being formed from surfaces of said mounting sections over which strings are passed and being located in predetermined alignment with said sockets forming guiding, bearing, and/ or anchorage elements against which the strings may be engaged and maintained in predetermined alignment for locating the strings forming separate notes with respect to each other and providing bearing surfaces which determine one end of the speaking length of the strings, and those of said projections forming said bearing elements including a bearing surface elongated substantially perpendicular to the direction in which strings are placed thereon, and being of suflicient length to engage only those strings cooperating to form a single note.

References Cited by the Examiner UNITED STATES PATENTS 2,858,723 11/58 Wickharn 84-188 'LEO SMILOW, Primary Examiner. 

1. A PIANO PLATE OF THE CHARACTER DESCRIBED, COMPRISING A CAST METAL BODY INCLUDING UPPER AND LOWER STRING MOUNTING SECTIONS BETWEEN WHICH THE STRINGS ARE EXTENDED, MEANS PROVIDING HITCH PIN ANCHORAGES IN SAID LOWER SECTION ABOUT WHICH THE STRINGS MAY BE WRAPPED IN PASSING FROM ONE TUNING PIN TO ANOTHER, STRING BEARING SURFACES FORMED AS A PLURALITY OF SEPARATE INTEGRAL PROJECTIONS FROM THE SURFACE OF AT LEAST ONE OF SAID SECTIONS IN PREDETERMINED 